Search found 417 matches

by D Sceviour
Tue Jun 11, 2019 3:55 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: The Poor Man's KP Bitbase
Replies: 5
Views: 433

Re: The Poor Man's KP Bitbase

This KP bitbase version updates a few more draw positions. Some test positions are included. The extra draws will not make much difference. The strength of the KP bitbase is in its resiliency and residency, and not its completeness. The idea is to prune known positional draws and to reduce nodes on ...
by D Sceviour
Tue Jun 11, 2019 12:12 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Using evaluation hash score as current bestscore (initial guess)
Replies: 13
Views: 593

Re: Using evaluation hash score as current bestscore (initial guess)

upper hash < static - use the lower score upper hash > static - could still be a safe prune lower hash < static - looks like a safe prune lower hash > static - worth extending so make best_score = hash_score - to raise cutoff value and re-look at the position a little wider. use the higher score
by D Sceviour
Mon Jun 10, 2019 1:36 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: The Poor Man's KP Bitbase
Replies: 5
Views: 433

Re: The Poor Man's KP Bitbase

Notice that for the first two possibilities, the position of the strong king is irrelevant. The draw only depends on the position of the weak black king. We can almost solve the entire KPK ending without knowing the position of the white king! For example, in the following position the white king c...
by D Sceviour
Mon Jun 10, 2019 11:44 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: The Poor Man's KP Bitbase
Replies: 5
Views: 433

Re: The Poor Man's KP Bitbase

Just a question : in your code, kingsq is the square of the losing king right ? Hello Dany, Yes. The position of the winning king is always ignored! Does the kp table is filled when you run the engine? Yes, the initialization code is very fast - in pica seconds? :-) Sq-8 is the square in front, rig...
by D Sceviour
Fri Jun 07, 2019 12:54 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Using evaluation hash score as current bestscore (initial guess)
Replies: 13
Views: 593

Re: Using evaluation hash score as current bestscore (initial guess)

Indeed, I understand well why and how those scores are used, I wonder how they can be used the same way, one being an eval score (probably on a board with hanging pieces !) and the other being a more correct search score. I don't get how the same pruning margins can be used with both ? It is not cl...
by D Sceviour
Fri Jun 07, 2019 1:05 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: The Poor Man's KP Bitbase
Replies: 5
Views: 433

The Poor Man's KP Bitbase

Why use the poor man's king-pawn (KP) bitbase? First, the bitbase is only 3K and thus very easy on resources. It could be compressed even further to 1.5K, but 3K is small enough to easily fit into the modern hardware cache. More compression may not be desirable because it will require extra decompre...
by D Sceviour
Thu Jun 06, 2019 10:53 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Using evaluation hash score as current bestscore (initial guess)
Replies: 13
Views: 593

Re: Using evaluation hash score as current bestscore (initial guess)

You will often see a needed estimate for the score of a move. If the move is already in the hash table, then that is used as the estimate. If the move is not in the hash, then eval() is called to create an estimate. Usually this is used for pruning decisions {typically in null move processing} rath...
by D Sceviour
Thu Jun 06, 2019 9:39 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Using evaluation hash score as current bestscore (initial guess)
Replies: 13
Views: 593

Re: Using evaluation hash score as current bestscore (initial guess)

It may be that we want a static evaluation to determine whether the position is improving. This is how various selective searches can make comparisons. The hash score is not effective to determine if the position is improving from the previous position since it represents a bound that may be higher ...
by D Sceviour
Mon May 27, 2019 9:35 pm
Forum: Computer Chess Club: General Topics
Topic: Schooner 2.0.34 (UCI) and ponder
Replies: 7
Views: 907

Re: Schooner 2.0.34 (UCI) and ponder

I've made some quick tests @ 1'+2", unfortunately Schooner exceeds the time very often. Hopefully the author implement ponder for the uci-version too. Best wishes, G.S. (CEGT team) Just noticed this post. The problem as I see it is that UCI protocol requires the engine to submit a ponder move for c...
by D Sceviour
Sat May 11, 2019 11:04 am
Forum: Computer Chess Club: Tournaments and Matches
Topic: 74th Amateur Series Division 1
Replies: 12
Views: 822

Re: 74th Amateur Series Division 1

Schooner never won a game, although it did draw with Fire and Stockfish. This group stands in an untouchable class by itself. Whichever engine wins Division 2 will face rough treatment here. Thank you to Graham for keeping up with the division contests.